Tool Shelf for Multifunction Scaffold

ABSTRACT

The claimed invention comprises a tool shelf for a multi-function scaffold comprising two spaced apart ladder frames supporting a platform and a guard rail mounted to the platform. The tool shelf is specially designed to mount to either the ladder frame, or to the guard rail system. When the platform is adjusted to the maximum height, the worker can mount the guard rail system so that the items placed on the tool shelf will be within reach without bending over. When the platform is lowered, the tool shelf can be mounted to the ladder frame.

RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application No. 63/239,785 filed Sep. 1, 2021, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to accessories for multifunction scaffolds and, more particularly, to a tool shelf capable of mounting to the multifunction scaffold in multiple configurations.

BACKGROUND

A typical multi-function scaffold comprises two ladder frames supporting an adjustable height platform. For safety, a guard rail system can be mounted to the platform to prevent a worker from falling from the platform. Tool shelves that attach to the ladder frame are known to make tools and other items readily accessible to a worker. Known tool shelves typically comprise a shelf that mounts to the ladder frame of the scaffold and is supported by one of the rungs of the ladder frame. However, when the platform is adjusted to its maximum height, the items place on the tool shelf will be out of the worker's reach and the worker may need to bend over to reach items placed on the tool shelf, which increases the likelihood of a fall and presents a safety hazard.

SUMMARY

The claimed invention comprises a tool shelf for a multi-function scaffold comprising two spaced apart ladder frames supporting a platform and a guard rail mounted to the platform. The tool shelf is specially designed to mount to either the ladder frame, or to the guard rail system. When the platform is adjusted to the maximum height, the worker can mount the to guard rail system so that the items placed on the tool shelf will be within reach without bending over. When the platform is lowered, the tool shelf can be mounted to the ladder frame.

In one embodiment, the tool shelf comprises a shelf comprising a top surface, front wall, back wall, and side walls. A first horizontal channel in the shelf extends parallel to the rear wall and configured to engage with a ladder rung of the ladder frame of the scaffold in a first mounting position and with a horizontal rail of the guard rail in a second mounting position such that the weight of the tool shelf is supported by the ladder rung on the ladder frame in a first mounting position and by the horizontal rail of the guard rail in a second mounting position. A pair of tiered slots extending inward from respective side walls adjacent the rear wall. Each tiered slot comprises a perimeter wall extending around the tiered slot, a first section configured to receive a vertical support of the ladder frame in the first mounting position with the perimeter wall engaging opposing sides of the vertical support of the ladder frame, and a second section configured to receive a vertical post of the guard rail in the second mounting position with the perimeter wall engaging opposing sides of the vertical post of the guard rail.

Another embodiment comprises a tool shelf adapted to mount to a guard rail extending around a platform of the scaffold. The shelf comprises a top surface, front wall, back wall, and side walls. A first horizontal channel in the shelf extends parallel to the rear wall and is configured to engage with a first horizontal rail of the guard rail in a first mounting position such that the tool shelf is supported on one side by the horizontal member and that the tool shelf extends outward from the guard rail. At least one detachable mounting arm is provided and configured to engage with a second horizontal member of the guard rail in the first mounting position so as to hold the tool shelf in a horizontal orientation.

Another embodiment comprises a tool shelf adapted to mount to a guard rail extending around a platform of the scaffold. The shelf comprises a top surface, front wall, back wall, and side walls. A pair of first horizontal channels in the shelf extend parallel to the respective side walls on opposing sides of the tool shelf, the horizontal channels being configured to engage with first horizontal rails of the guard rail on opposing sides of the platform in a first mounting position such that the tool shelf is supported on two sides by the horizontal rails of the guard rail.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of the multifunction scaffold with two ladder frames and an adjustable height platform.

FIG. 2 illustrates one of two side rail assemblies of the adjustable height platform.

FIG. 3 is a perspective view of a guard rail system for a multi-function scaffold.

FIG. 4 is a perspective view of a tool shelf for the multifunction scaffold showing the top and rear side

FIG. 5 is a perspective view of a tool shelf for the multifunction scaffold showing the top and front side.

FIG. 6 is a perspective view of a tool shelf for the multifunction scaffold showing the bottom and front side.

FIG. 7 is a top view of a tool shelf for the multifunction scaffold.

FIG. 8 is a front elevation view of a tool shelf for the multifunction scaffold.

FIG. 9 is a side view of a tool shelf for the multifunction scaffold.

FIG. 10 is a bottom view of a tool shelf for the multifunction scaffold.

FIG. 11 is perspective view illustrating four different mounting positions.

FIG. 11A is perspective view illustrating four different mounting positions.

FIG. 12 is a perspective view from the top showing a tool shelf in mounting position A.

FIG. 13 is a perspective view from the bottom showing a tool shelf in mounting position A.

FIG. 14 is a perspective view from the top showing a tool shelf in mounting position B.

FIG. 15 is a perspective view from the top showing a tool shelf in mounting position C.

FIG. 16 is a perspective view from the top showing a tool shelf in mounting position D.

FIG. 17 is a detail view of the multi-tier slot in the tool shelf.

FIG. 18 is a detail view showing the engagement of the tool shelf with the vertical supports of the ladder frame in mounting position A.

FIG. 19 is a detail view showing the engagement of the tool shelf with the vertical posts of the guard rail in mounting position B.

DETAILED DESCRIPTION

The present disclosure relates to a tool shelf designed for use with a multi-function scaffold. The tool shelf is specially designed to mount in a variety of different positions depending upon the needs of the worker. To provide context for a full understanding of the disclosure, a brief description of the multi-function scaffold is provided.

FIG. 1 illustrates a multi-purpose scaffold 10 according to an exemplary embodiment. The multi-purpose scaffold 10 comprises two ladder frames 12 and an adjustable height platform 20 supported between the two ladder frames 12. The adjustable height platform 20 can be mounted between the ladder frames 12 in two different orientations depending on a height requirement for a task. The first orientation enables the platform 20 to be adjusted to its maximum height. The second orientation enables the platform 20 to be adjusted to its minimum height.

Each ladder frame 12 comprises two vertical supports 14 connected by two or more cross members 16 that serve as ladder rungs. The vertical supports 14 and cross members 16 are preferably made of a metal tubing or other rigid tubular material. The cross members 16 are preferably welded at each end to respective ones of the vertical supports 14 so that each ladder frame 12 is a unitary structure. A series of aligned openings 18 extend through the vertical supports 14 perpendicular to the plane of the ladder frame 12 and are spaced 2 inches apart. As will be hereinafter described in more detail, the openings 18 are engaged by a releasable locking mechanism 30 (FIG. 2 ) on the platform 20 to secure the platform 20 at a desired height between the ladder frames 12.

Casters 50 or other ground-engaging members can be inserted into the lower ends of the vertical supports 14 and secured by a span pin 56. The caster 50 includes a stem (not shown) that inserts into the end of the vertical support 14. The stem includes an opening that aligns with the opening 18 in the vertical support 14 to allow insertion of the span pin 56 to secure the caster 50 to the vertical support 14.

The platform 20 comprises two side rail assemblies that extend between the ladder frames 12 and a deck 40 that is supported by the side rail assemblies. The side rail assemblies are shown in FIG. 2 . Each side rail assembly comprises a side rail 22 and two guide channels 24 at opposing ends of the side rail 22. A sleeve 26 for mounting a guard rail assembly 100 as hereinafter described is interposed between each end of the side rail 22 and the guide channel 24. The sleeve 26 includes an opening 28 for a span pin.

The side rails 22 are symmetrical about a horizontal plane and configured to provide a support surface for the deck 40 of the platform 20 in both a first orientation (guide channels 24 extending down from side rail 22) and a second orientation (guide channels 24 extending up from side rail 22). The platform 20 can be used in either orientation. The side rails 22 are equipped with removable locking pins 42 to hold the deck 40 down once the deck 40 is put in place. The locking pins 42 are removable and can be installed in both orientations of the platform 20.

The guide channels 24 comprises a C-shaped channels 24 and are configured to slide along the vertical supports 14 of the ladder frames 12 at each end of the scaffold 10 to adjust the height of the platform 20. Each guide channel 24 includes a releasable locking mechanism 30 for locking the platform 20 at a desired height. In one embodiment, the releasable locking mechanism 30 comprises a U-shaped locking pin 32 that engages with aligned openings and in the guide channel 24 and vertical supports 14 respectively to lock the platform 20 at a desired height. The U-shaped locking pin 32 is biased by springs to an engaged position in which the ends of the locking pin 32 are engaged in holes 18 in the vertical supports 14. To adjust the height of the platform 20, the locking pin 32 is pulled back to disengage the locking pin 32 from the holes 18 in the vertical supports 14. Once disengaged, the platform 20 can be adjusted in height to any desired position in the adjustment range. When the platform 20 is adjusted to the desired height, span pins 34 (FIG. 1 ) can be inserted through holes in the guide channel 24 that align with the holes 18 in the vertical supports 14 as a fail safe. The span pins 34 secure the platform 20 at the desired height even if the releasable locking mechanism fails or disengages.

FIG. 3 illustrates a guard rail system 100 for use with the multifunction scaffold 10. The guard rail system 100 is designed to removably mount to the side rail assemblies of the platform 20 as hereinafter described. Generally, the guard rail assembly 100 comprises two side rail assemblies 120 and two gates 140. The side rail assemblies 120 of the guard rail system 100 each comprise two vertical posts 122 connected by horizontal rails 124 and a guard plate 128. The lower ends of the vertical posts 122 includes mounting blocks 112 configured to be inserted into the sleeves 26 on the side rails 22 for the adjustable platform 20. The vertical posts 122 can be secured in place by span pins that pass through aligned holes in the sleeve 26 and mounting block 112. The gates 140 each comprise two vertical posts 142 interconnected by horizontal rails 144 and a guard plate 148. The gates 140 are hingedly connected to a side rail 120 by hinges 150 on one side of the gate 140. The opposite side of the gate includes a latch element 152 that mates with a latch element 154 on the side rail 120 opposite the hinge 150. The gates 140 are flush with the ends of the side rail assemblies 120 so that the vertical posts 122, 142 of the side rail assemblies 120 and gates 140 respectively align in a straight line. In some embodiments, the vertical posts 142 of the gates 140 extend above the top horizontal rail 144 to facilitate mounting of the tool shelf 200 as hereinafter described.

FIGS. 4-10 illustrate a tool shelf 200 designed for use with the multi-function scaffold 10 has hereinabove described. As shown in FIGS. 11 and 11A, the tool shelf 200 is designed to mount to the multi-function scaffold 10 in a variety of different configurations denoted a Positions A-F. The tool shelf 200 generally comprises a molded shelf 202 and two mounting arms 280 for use in mounting the tool shelf to the guard rail 100 in mounting position B and D.

The molded shelf 202 comprises a top surface 204, side walls 206, front wall 208 and rear wall 210. The side walls 206, front wall 208 and rear wall 210 extend downward from the top surface 204. A plurality of reinforcing ribs 212, seen best in FIGS. 6 and 10 , extend downward from the underside of the top surface 204 to add strength and rigidity to the tool shelf 200.

The top surface 204 of the tools shelf 200 has a number of integrally formed features providing a place to store or support various items used by a worker. The features include a main tray 220, a side tray 226, a cup 228 and a plurality of tool holders 230-236. The main tray 220 comprises a shallow recess in the top surface 204. Two concentrically arranged circular recess 222, 224 are formed in the main tray 220 and are sized to receive paint cans of different dimensions. A side tray 226 is formed in the top surface 204 on one side of the main tray 220, which is slightly deeper than the main tray 220. The side tray 226 may be used, for example, to hold small items such as screws, washer, nuts, etc. A cup 228 is formed in the top surface 204, which is deeper than the side tray 226. The cup 228 provides another place to store relatively small items that are being used. A variety of openings are formed in the top surface to serve as tool holders 230-236. In the exemplary embodiments, the tool shelf 200 includes tool holders 230 configured to receive a drill or other power tool, tool holders 232 configured to receive a hammer, tool holders 234 configured to hold various types of pliers, and tool holders 236 along the front and rear edges configured to hold screw drivers.

A pair of recesses 240 are formed in the front wall 208 of the molded shelf 202 and include integrally molded hooks 238. The hooks 238 provide means for hanging tools or other items.

The rear wall 210 includes a pair openings 244 adjacent opposing ends of the real wall 210. The openings 244 are configured to receive mounting arms for mounting the tool shelf 200 to the scaffold 10 in mounting positions B and D. The rear wall 210 terminates short of the side wall 206 to provide clearance when the tool shelf is mounted to the guard rails as will be hereinafter described.

Tiered slots 250 are formed in the tool shelf 200 at the junction of the side walls 206 and rear wall 210. The tiered slots 250 extend vertically through the tool shelf 200 and comprise three tiers or sections denoted as the outer or outer section 252, the middle tier or middle section 254, and the inner tier or inner section 256. The tiered slot 250 is specially configured to engage with the vertical supports 14 of the ladder frame 12 in mounting position A (FIG. 18 ) and with the vertical posts 142 of the guard rail in mounting positions B (FIG. 19 ).

Referring to FIG. 17 , a perimeter wall 258 of the tiered slot 250 extends from point A at the rear end of the side wall 206 to point F on the rear wall 210. From point A to point B, the perimeter wall 258 extends generally parallel to the front and rear walls 208, 210 of the tool shelf 200 and forms one lateral wall of the outer section 252 and middle section 254 of the tiered slot 250. Between points B to point C, the perimeter wall 258 defines an open slot that extends inward and terminates at a rounded end to form the inner section 256 of the tiered slot 250. Between points C and D, the perimeter wall 258 defines a shoulder bordering the middle section 254. From point D to point E, the perimeter wall 258 extends generally parallel to the front and rear walls 208, 210 of the tool shelf 200 and forms a second lateral wall of the middle section 254 of the tiered slot 250. The outer section 252 has only one lateral wall. Between points E and F, the perimeter wall 258 defines another shoulder bordering the outer section 252. Note that the shoulder between points E and F is set back relative to the side wall 206 to provide clearance for the horizontal rails 124 of the guard rail assembly 100 when the tool shelf 200 is used in mounting position B (FIG. 19 ).

The tool shelf 200 includes a channel 260 on the underside of the tool shelf 200 extending parallel to the rear wall 210 between the tiered slots 250. The channel 260 is formed by cutting way portions of the perimeter wall 258 and reinforcing ribs 212 on the underside of the tool shelf 200. The cut away portions of the perimeter wall 258 and reinforcing ribs 212 align along a longitudinal axis that extends parallel to the rear wall 210 and aligns with the tiered slots 250. The channel 260 receives one of the cross members 16, i.e., ladder rungs, of the ladder frame 12 when the tool shelf 200 is mounted in mounting position A so that the cross member 16 supports the weight of the tool shelf 200. The channel 260 receives one of the horizontal rails 144 of the gate 140 when the tool shelf 200 is mounted in mounting positions B and D so that the horizontal rail 144 supports the weight of the tool shelf 200.

The tool shelf 200 further includes two side channels 270 on the underside of the tool shelf 200 extending parallel to the side walls 206. The channels 270 are formed by cutting way portions of the front wall 208, rear wall 210, perimeter wall 258 and reinforcing ribs 212 on the underside of the tool shelf 200. The cut away portions of the front wall 208, rear wall 210, perimeter wall 258 and reinforcing ribs 212 align along a longitudinal axis that extends parallel to the side walls 206. The spacing between the channels 270 matches the spacing between the side rail assemblies 120 so that the tool shelf 200 can rest on two opposing guard rails. The channels 270 receive the horizontal rails 124 of the side rail assemblies 120 when the tool shelf 200 is mounted in mounting position C so that the horizontal rails 124 support the weight of the tool shelf 200.

Mounting arms 280, also referred to herein as elbows 280, are provided to facilitate mounting the tool shelf 200 to the guard rail 100 in mounting positions B and D. Each mounting arm 280 includes a connecting portion 282 and a finger portion 284. The connecting portion 282 is configured to insert into a respective opening 244 in the rear wall 210 of the tool shelf 200. The finger portion 284 extends laterally outward and downward from the connecting portion 282 and is configured to engage an underside of the horizontal rails 124 of the side rail assemblies 120 in mounting positions B and D. A bore 286 extends vertically through the end of the connecting portion 282 and aligns with the opening 246 in the tool shelf 200. When the mounting arm 280 is inserted into the opening 244 in the tool shelf 200, a securing pin 288 can be inserted through the aligned openings 246 and 286 in the tool shelf 200 and mounting arm 280 respectively to secure the mounting arm 280 to the tool shelf 200. When the mounting arms 280 are not in use, the mounting arms 280 and securing pin 288 can be stored on the underside of the tool shelf 200 as shown in FIG. 10 . The underside of the tool shelf 200 includes gripping features to retain the mounting arms 280 and securing pin 288 when not in use.

FIGS. 11 and 11A illustrate various ways in which the mounting shelf 200 can be mounted to the multi-function scaffold 100 and guard rail 100. Six different mounting positions are shown denoted as mounting positions A-F.

In mounting position A, shown in FIGS. 12 and 13 , the vertical supports 14 of the ladder frame 12 are received in the middle section 254 of the tiered slot 250 and the rear side of the tool shelf 200 rests on one of the ladder rungs 16 of the ladder frame 12. The ladder rung 16 extends through the channel 260 running parallel to the rear wall 210. In this position, the weight of the tool shelf 200 is carried primarily by the ladder rung 16. The engagement of the perimeter wall 258 of the slot 250 with the vertical supports 14 of the ladder frame 12 prevents the tool shelf 200 from tilting downward. When weight is placed on the tool shelf 200, the perimeter walls 258 binds against the vertical supports 14 which helps to support the weight. The engagement of the perimeter wall 258 with the vertical supports 14 thus holds the tool shelf 200 in a generally horizontal orientation.

In mounting position B, shown in FIG. 14 , the vertical posts 142 of the gates 140 on the guard rail assembly 100 are received in the inner section 256 of the tiered slot 250 and the rear side of the tool shelf 200 rests on one of the horizontal rails 144 of the gate 140. The horizontal rail 144 of the gate 140 extends through the channel 260 running parallel to the rear wall 210. In this position, the weight of the tool shelf 200 is carried primarily by the horizontal rail 144 of the gate 140. The engagement of the perimeter wall 258 of the slot 250 with the vertical posts 142 of the gate 140 prevents the tool shelf 200 from tilting downward. When weight is placed on the tool shelf 200, the perimeter wall 258 binds against the vertical posts 142 which helps to support the weight.

In mounting position B, the mounting arms 280 may optionally be used to provide additional support for the tool shelf 200. In this case, the mounting arms 280 are inserted into the openings 244 in the rear wall. The fingers 284 of the mounting arms 280 extend outward and engage the underside of a horizontal rails 124 of the side rail assemblies 120. The tool shelf 200 itself engages the top side of the horizontal rails 124 at a position spaced from the finger 286 of the mounting arm 280. The engagement of the fingers 284 with the bottom side of the horizontal rails 124 prevents the tool shelf 200 from tilting downward.

Those skilled in the art will appreciate that the use of the mounting arms or elbows 280 in mounting position B is not required. As noted, when weight is placed on the tool shelf 200, the perimeter wall 258 binds against the vertical posts 142 which prevents the tool shelf 200 from tilting downward.

In mounting position C, shown in FIG. 15 , the tool shelf 200 rests on the horizontal rails 124 of the side rail assemblies 120 on opposite sides of the guard rail 100. The horizontal rails 124 of the side rail assemblies 120 extend through respective channels 270 running parallel to the side walls 206. In this position, the weight of the tool shelf 200 is carried by the horizontal rails 124 of the side rail assemblies 120. In a variation of this position labeled as mounting position E in FIG. 11 , the tool shelf 200 can be supported between the side rail assemblies 120 with the vertical posts 142 of the gates 140 received in and extending through the inner section 256 of the tiered slots 250. In this case, the horizontal rail 144 of the gate 140 extends through the channel 260 running parallel to the rear wall 210 so that the tool shelf 200 is supported on three sides. In another variation labeled as mounting position F in FIG. 11 , the tool shelf 200 can be supported between the side rail assemblies 120 and topmost horizontal rail 144 of the gate 140 so that the tool shelf 200 is supported on three sides.

In mounting position D shown in FIG. 16 , the tool shelf 200 is mounted on the uppermost horizontal rail 144 of a gate 140 on one end of the guard rail assembly 100. In this position, the horizontal rail 144 of the gate 140 extends through the channel 260 running parallel to the rear wall 210 so that horizontal rail 144 supports the weight of the tool shelf 200. In this position, the vertical posts 142 of the gate do not extend through the tiered slot 250 so there is nothing to prevent the tool shelf 200 from tilting downward. To hold the tool shelf 200 in place, the mounting arms 280 are inserted into the openings 244 in the rear wall. The fingers 284 of the mounting arms 280 extend outward and engage the underside of a horizontal rails 124 of the side rail assemblies 120. The tool shelf 200 itself engages the top side of the horizontal rails 124 at a position spaced from the finger 286 of the mounting arm 280. The engagement of the horizontal rails 124 on the top and bottom sides at spaced apart locations prevents the tool shelf 200 from tilting downward.

In some embodiments, the tool shelf 200 could be installed on the top rail 144 of the gates 140 without the use of the mounting arms or elbows 280 by extending the vertical posts 142 of the gates 140 above the top rail 144. In this case, the vertical posts 142 of the gate 140 extend through the middle section of the tiered slots, which prevents the tool shelf 200 from tilting downward as previously described.

With some modification, the tool shelf 200 could also be mounted to the horizontal rail 124 of the side rail assemblies 120. For example, the tool shelf 200 could rest on the topmost horizontal rail 124, which can be received in the channel 260 adjacent the rear wall 210. A telescoping brace (not shown) can be provided that extends downward from a point near the front wall 208 and connects to the next lower horizontal rail 124. When not in use, the brace can be retracted and stored on the underside of the tool shelf.

The present invention provides a more versatile tool shelf that can be positioned on the scaffold in a variety of different location depending on the needs of the user. The tool shelf allows the user to keep tools and other items needed for a job within easy reach and improves worker productivity.

The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein. 

What is claimed is:
 1. A tool shelf for a scaffold comprising two spaced apart ladder frames supporting a platform and a guard rail extending around the platform, the tool shelf comprising: a shelf comprising a top surface, front wall, back wall, and side walls; a first horizontal channel extending parallel to the rear wall and configured to engage with a ladder rung of the ladder frame of the scaffold in a first mounting position and with a horizontal rail of the guard rail in a second mounting position such that the weight of the tool shelf is supported by the ladder rung on the ladder frame in a first mounting position and by the horizontal rail of the guard rail in a second mounting position; a pair of tiered slots extending inward from respective side walls adjacent the rear wall, each tiered slot comprising: a perimeter wall extending around the tiered slot; a first section configured to receive a vertical support of the ladder frame in the first mounting position with the perimeter wall engaging opposing sides of the vertical support of the ladder frame; and a second section configured to receive a vertical post of the guard rail in the second mounting position with the perimeter wall engaging opposing sides of the vertical post of the guard rail.
 2. The tool shelf of claim 1, further comprising a pair of second horizontal channels extending parallel to the respective side walls on opposing sides of the tool shelf, the second horizontal channels being configured to engage with respective horizontal rails of the guard rail on opposing sides of the platform in a third mounting position such that the tool shelf is supported on two opposing sides by the horizontal members of the guard rail.
 3. The tool shelf of claim 2, wherein the first horizontal channel further engages with a third horizontal rail of the guard rail in the third mounting position such that the tool shelf is supported on three sides in the third mounting position.
 4. The tool shelf of claim 1, further comprising at least one detachable mounting arm configured to engage with a second horizontal member of the guard rail so as to hold the tool shelf in a horizontal orientation in the second mounting position or a third mounting position.
 5. The tool shelf of claim 4, wherein the detachable arm is configured to engage with a horizontal rail of the guard rail in the third mounting position.
 6. The tool shelf of claim 4, further comprising one or more openings in a rear wall of the tool shelf configured to receive the detachable mounting arms while in use.
 7. The tool shelf of claim 4, further comprising gripping features on an underside of the tool shelf for storing the detachable mounting arm when not in use.
 8. The tool shelf of claim 1, further comprising one or more tool holders formed in a top surface of the tool shelf.
 9. The tool shelf of claim 1, further comprising one or more cups or trays formed in a top surface of the tool shelf.
 10. The tool shelf of claim 1, further comprising one or more hooks formed in a front wall of the tool shelf.
 11. A tool shelf adapted to mount to a guard rail extending around a platform of a scaffold, the tool shelf comprising: a shelf comprising a top surface, front wall, back wall, and side walls; a first horizontal channel extending parallel to the rear wall and configured to engage with a first horizontal rail of the guard rail in a first mounting position such that the tool shelf is supported on one side by the horizontal member and that the tool shelf extends outward from the guard rail; and at least one detachable mounting arm configured to engage with a second horizontal member of the guard rail in the first mounting position so as to hold the tool shelf in a horizontal orientation.
 12. The tool shelf of claim 10, further comprising one or more openings in a rear wall of the tool shelf configured to receive the detachable mounting arms while in use.
 13. The tool shelf of claim 10, further comprising gripping features on an underside of the tool shelf for storing the detachable mounting arm when not in use.
 14. The tool shelf of claim 11, further comprising: a pair of slots extending inward from respective side walls adjacent the rear wall, each slot comprising a perimeter wall extending around the slot and being configured to receive, in the first mounting position, a vertical post of the guard rail with the perimeter wall engaging opposing sides of the vertical post of the guard rail.
 15. The tool shelf of claim 11, wherein each slot is further configured to receive a vertical support of a ladder frame for the scaffold in a second mounting position.
 16. The tool shelf of claim 15, wherein the first horizontal channel is configured to engage a ladder rung of the ladder frame in the second mounting position.
 17. The tool shelf of claim 15, wherein each slot is tiered and includes a first section to receive the vertical support of the ladder frame in the second mounting position and a second section configured to receive the vertical post of the guard rail in the first mounting position.
 18. The tool shelf of claim 11, further comprising: a pair of second horizontal channels extending parallel to the respective side walls on opposing sides of the tool shelf, the second horizontal channels being configured to engage with respective horizontal rails of the guard rail on opposing sides of the platform in a third mounting position such that the tool shelf is supported on two opposing sides by the horizontal members of the guard rail.
 19. The tool shelf of claim 18, wherein the first horizontal channel further engages with a first horizontal rail of the guard rail in the third mounting position such that the tool shelf is supported on three sides in the third mounting position.
 20. A tool shelf adapted to mount to a guard rail extending around a platform of a scaffold, the tool shelf comprising: a shelf comprising a top surface, front wall, back wall, and side walls; a pair of first horizontal channels extending parallel to the respective side walls on opposing sides of the tool shelf, the horizontal channels being configured to engage with first horizontal rails of the guard rail on opposing sides of the platform in a first mounting position such that the tool shelf is supported on two sides by the horizontal rails of the guard rail.
 21. The tool shelf of claim 20, further comprising a second horizontal channel extending parallel to the rear wall and configured to engage with a second horizontal rail of the guard rail in the first mounting position such that the tool shelf is supported on three sides in the first mounting position.
 22. The tool shelf of claim 21, wherein the second horizontal channel is configured to engage with the third horizontal rail in a second mounting position.
 23. The tool shelf of claim 22, further comprising at least one detachable mounting arm configured to engage with one of the first horizontal rails of the guard rail in the second mounting position.
 24. The tool shelf of claim 23, further comprising one or more openings in a rear wall of the tool shelf configured to receive the detachable mounting arms while in use.
 25. The tool shelf of claim 23, further comprising gripping features on an underside of the tool shelf for storing the detachable mounting arm when not in use.
 25. The tool shelf of claim 21, further comprising: a pair of slots extending inward from respective side walls adjacent the rear wall, each slot comprising a perimeter wall extending around the slot and being configured to receive, in the second mounting position, a vertical post of the guard rail with the perimeter wall engaging opposing sides of the vertical post of the guard rail.
 26. The tool shelf of claim 25, wherein each slot is further configured to receive a vertical support of a ladder frame for the scaffold in a third mounting position.
 27. The tool shelf of claim 26, wherein each slot is tiered and includes a first section to receive the vertical support of the ladder frame in the third mounting position and a second section configured to receive the vertical post of the guard rail in the second mounting position.
 28. The tool shelf of claim 26, wherein the second horizontal channel is configured to engage the ladder rung in the third mounting position. 